Two-Year Changes in Physical Activity and Concurrent Changes in Cognitive Function in a Cohort of Adults with Metabolic Syndrome

BACKGROUND

It has been proposed that physical activity (PA) could prevent cognitive decline.

OBJECTIVE

To evaluate the association between changes in PA and changes in cognitive function in a cohort of adults with metabolic syndrome.

METHODS

Longitudinal observational study including 5,500 adults (mean age 65 years, SD = 5; women = 49.3% ) with metabolic syndrome. Participants underwent physical activity measurements and cognitive evaluation at baseline and at two-years of follow-up. PA was quantified using the Minnesota questionnaire-shortened version. Cognitive function was evaluated using a battery of tests: Mini-Mental Test Examination, Clock Drawing Test, Trail Making Test A and B, Verbal Fluency Test, and Digit Span. The primary outcome was two-year change in cognition, measured through the Global Composite Score (GCS) of all neuropsychological tests. Multivariable-adjusted linear regression models were fitted with baseline PA and their changes as the main exposures and changes in cognitive function as the outcome.

RESULTS

No significant association was found between PA levels (or their changes) in the GCS of cognitive function. A greater increase in PA levels was associated with a more favorable two-year change in the Trail Making Test A (Q4 versus Q1: b = - 2.24s, 95% CI -4.36 to -0.12s; p-trend = 0.020). No significant association was found for other neuropsychological test.

CONCLUSION

Our results do not support an association between increases in PA and the evolution of the global cognitive function at two-year in an intervention trial which included PA promotion in one of its two randomized arms, but they suggested a possible beneficial effect of PA on attentional function in older adults.

Validity of the energy-restricted Mediterranean Diet Adherence Screener

BACKGROUND

Short dietary assessment tools can be useful to estimate food intake and diet quality in large-scale epidemiological studies with time constraints.

OBJECTIVE

To determine the concurrent validity of the 17-item energy-restricted Mediterranean Adherence Screener (er-MEDAS) used in the PREDIMED (PREvención con DIeta MEDiterránea)-Plus trial and to analyse its capacity to detect 1-year changes in diet and cardiometabolic risk factors.

METHODS

Validation study nested in the PREDIMED-Plus (n = 6760, 55-75 years). Dietary data were collected by the 17-item er-MEDAS and a 143-item validated semiquantitative food frequency questionnaire (FFQ) at baseline and after 1-year intervention. Cardiometabolic risk markers were measured at both time points. A Mediterranean diet (MedDiet) score was derived from both instruments. Concurrent validity was evaluated by Pearson and intra-class correlation coefficients (ICC) and Bland and Altman limits of agreement. Construct validity was evaluated by assessing 1-year changes in FFQ-reported dietary intake and cardiometabolic profile changes in relation to changes in er-MEDAS.

RESULTS

A moderate to good correlation between the MedDiet score calculated by both measurement instruments was found: r = 0.61 and ICC = 0.60 (both p < 0.001). Agreement of each of the er-MEDAS items ranged from 55.4% to 85.0% with a moderate mean concordance (kappa = 0.41). Between baseline and 1-year follow-up, energy intake measured by the FFQ decreased by 242 kcal, while Mediterranean food consumption increased in participants with the highest increase in the er-MEDAS MedDiet score. An increase in the er-MEDAS MedDiet score ratings was associated with a decrease in BMI, waist circumference, triglycerides, fasting glucose, diastolic blood pressure, and triglycerides/HDL-cholesterol ratio (p < 0.001 for all), and with an increase in HDL-cholesterol (p = 0.006).

CONCLUSION

The er-MEDAS shows a modest to good concurrent validity compared with FFQ data. It shows acceptable construct validity, as a greater er-MEDAS score was associated with more favourable dietary and cardiometabolic profiles over time.

TRIAL REGISTRY

ISRCTN89898870; registration date, 24 July 2014. https://www.isrctn.com/ISRCTN89898870.

Anthropometric variables as mediators of the association of changes in diet and physical activity with inflammatory profile

BACKGROUND

Mechanisms underlying the associations of high levels of physical activity (PA) and adherence to the Mediterranean Diet (MedDiet) with a better inflammatory profile remain unclear. Our objective was to assess the mediating role of changes in body mass index (BMI) and waist circumference (WC), as markers of body fat in the association of changes in PA and adherence to the MedDiet, with changes in the inflammatory profile.

METHODS

This study included 489 adults, aged 55 to 75 years, from the PREDIMED-Plus multi-centre lifestyle intervention trial. An inflammatory score was calculated, based on 8 blood biomarkers: high-sensitivity C-reactive protein, interleukin 6, interleukin 8, interleukin 18, monocyte chemo-attractant protein-1, C-peptide, leptin, and regulated on activation, normal T-cell expressed and secreted chemokine (RANTES). Biomarkers, levels of PA, score of MedDiet adherence, BMI and WC were measured at baseline and at one-year follow-up. Linear regression models were fitted according to the Baron and Kenny framework for mediation analysis.

RESULTS

Changes in BMI and WC mediated the association of both changes in PA and changes in the MedDiet adherence with the inflammatory score. BMI mediated 26% of the association of changes in total PA with the inflammatory profile, and 27% of the association of changes in the MedDiet, while WC mediated 13% and 12% of these associations, respectively.

CONCLUSION

In older adults at high cardiovascular risk, increasing PA levels and adherence to a MedDiet during 1 year were associated with a lower inflammatory score, which was partly mediated by a reduction in body fat.

Effectiveness of the physical activity intervention program in the PREDIMED-Plus study: a randomized controlled trial

BACKGROUND

The development and implementation of effective physical activity (PA) intervention programs is challenging, particularly in older adults. After the first year of the intervention program used in the ongoing PREvención con DIeta MEDiterránea (PREDIMED)-Plus trial, we assessed the initial effectiveness of the PA component.

METHODS

PREDIMED-Plus is an ongoing randomized clinical trial including 6874 participants randomized to an intensive weight-loss lifestyle intervention based on an energy-restricted Mediterranean diet (MedDiet), physical activity promotion and behavioral support and to a control group using MedDiet recommendations but without calorie restriction or PA advice. Body mass index (BMI) and waist circumference (WC) are measured by standard clinical protocols. Duration and intensity of PA is self-reported using the validated REGICOR Short Physical Activity Questionnaire. The primary endpoint of the PREDIMED-Plus trial is a combined cardiovascular outcome: myocardial infarction (acute coronary syndromes with positive troponin test), stroke, or cardiovascular mortality. The present study involved secondary analysis of PA data (n = 6059; mean age 65 ± 4.9 years) with one-year changes in total, light, and moderate-to-vigorous PA within and between intervention groups as the outcome. Generalized estimating equation models were fitted to evaluate time trends of PA, BMI, and WC within groups and differences between intervention and control groups.

RESULTS

After 12 months, average daily MVPA increased by 27.2 (95%CI 5.7;48.7) METs-min/day and 123.1 (95%CI 109.7-136.6) METs-min/day in the control and intervention groups, respectively. Total-PA, light-PA, and MVPA increased significantly (p < 0.01) in both groups. A significant (p < 0.001) time*intervention group interaction was found for Total-PA and MVPA, meaning the PA trajectory over time differed between the intervention and control groups. Age, sex, education level, and BMI did not moderate the effectiveness of the PA intervention. BMI and WC decreased significantly with increasing MVPA, compared with participants who reported no changes in MVPA.

CONCLUSION

After one year of follow-up, the PREDIMED-Plus PA intervention has been effective in increasing daily PA in older adults.

TRIAL REGISTRATION

Retrospectively registered at the International Standard Randomized Controlled Trial ( http://www.isrctn.com/ISRCTN89898870 ), registration date: 24 July 2014.

Mercury exposure and risk of cardiovascular disease: a nested case-control study in the PREDIMED (PREvention with MEDiterranean Diet) study

BACKGROUND

Substantial evidence suggests that consuming 1-2 servings of fish per week, particularly oily fish (e.g., salmon, herring, sardines) is beneficial for cardiovascular health due to its high n-3 polyunsaturated fatty acid content. However, there is some concern that the mercury content in fish may increase cardiovascular disease risk, but this relationship remains unclear.

METHODS

The PREDIMED trial included 7477 participants who were at high risk for cardiovascular disease at baseline. In this study, we evaluated associations between mercury exposure, fish consumption and cardiovascular disease. We randomly selected 147 of the 288 cases diagnosed with cardiovascular disease during follow-up and matched them on age and sex to 267 controls. Instrumental neutron activation analysis was used to assess toenail mercury concentration. In-person interviews, medical record reviews and validated questionnaires were used to assess fish consumption and other covariates. Information was collected at baseline and updated yearly during follow-up. We used conditional logistic regression to evaluate associations in the total nested case-control study, and unconditional logistic regression for population subsets.

RESULTS

Mean (±SD) toenail mercury concentrations (μg per gram) did not significantly differ between cases (0.63 (±0.53)) and controls (0.67 (±0.49)). Mercury concentration was not associated with cardiovascular disease in any analysis, and neither was fish consumption or n-3 fatty acids. The fully-adjusted relative risks for the highest versus lowest quartile of mercury concentration were 0.71 (95% Confidence Interval [CI], 0.34, 1.14; p_trend = 0.37) for the nested case-control study, 0.74 (95% CI, 0.32, 1.76; p_trend = 0.43) within the Mediterranean diet intervention group, and 0.50 (95% CI, 0.13, 1.96; p_trend = 0.41) within the control arm of the trial. Associations remained null when mercury was jointly assessed with fish consumption at baseline and during follow-up. Results were similar in different sensitivity analyses.

CONCLUSIONS

We found no evidence that mercury exposure from regular fish consumption increases cardiovascular disease risk in a population of Spanish adults with high cardiovascular disease risk and high fish consumption. This implies that the mercury content in fish does not detract from the already established cardiovascular benefits of fish consumption.

TRIAL REGISTRATION

ISRCTN35739639 .

Muscular fitness, fatness and inflammatory biomarkers in adolescents

BACKGROUND

Muscular fitness, cardiorespiratory fitness (CRF) and fatness are mutually related with chronic inflammation.

PURPOSE

To examine the independent association of muscular fitness with inflammatory biomarkers in adolescents from nine European countries.

METHODS

A total of 639 adolescents (296 boys) aged from 12.5 to 17.5 year were included in this report. Data collection took place in 2006-2007 and analyses in 2012. A muscular fitness score was computed from handgrip strength and standing long jump. CRF was measured using the 20 m shuttle run test. Z-scores of C-reactive protein, complement factors C3 and C4, leptin and white blood cell counts were summed to create a cluster of inflammatory biomarkers. Sex, age, pubertal stage and centre were used as main confounders. Additional models were further adjusted for insulin resistance (HOMA-IR) and sum of four skinfolds.

RESULTS

Muscular fitness was negatively associated with single and clustered inflammatory biomarkers (standardized β from -0.399 to -0.100, all P-values < 0.05). Additional adjustments for CRF and HOMA-IR weakened the associations, but they still remained significant. The association was no longer significant when adjusting for skinfolds. Decreasing values of inflammatory score were observed across incremental levels of muscular fitness in both non-overweight and overweight adolescents (P ≤ 0.05).

CONCLUSIONS

Adolescents with higher levels of muscular fitness present a lower chronic inflammation, and this seems to be explained by lower levels of fatness. Yet, overweight and obese adolescents may exhibit a less adverse profile if they maintain appropriate levels of muscular fitness.

Mediterranean diet reduces the adverse effect of the TCF7L2-rs7903146 polymorphism on cardiovascular risk factors and stroke incidence: a randomized controlled trial in a high-cardiovascular-risk population

OBJECTIVE

Transcription factor 7-like 2 (TCF7L2) polymorphisms are strongly associated with type 2 diabetes, but controversially with plasma lipids and cardiovascular disease. Interactions of the Mediterranean diet (MedDiet) on these associations are unknown. We investigated whether the TCF7L2-rs7903146 (C>T) polymorphism associations with type 2 diabetes, glucose, lipids, and cardiovascular disease incidence were modulated by MedDiet.

RESEARCH DESIGN AND METHODS

A randomized trial (two MedDiet intervention groups and a control group) with 7,018 participants in the PREvención con DIetaMEDiterránea study was undertaken and major cardiovascular events assessed. Data were analyzed at baseline and after a median follow-up of 4.8 years. Multivariable-adjusted Cox regression was used to estimate hazard ratios (HRs) for cardiovascular events.

RESULTS

The TCF7L2-rs7903146 polymorphism was associated with type 2 diabetes (odds ratio 1.87 [95% CI 1.62-2.17] for TT compared with CC). MedDiet interacted significantly with rs7903146 on fasting glucose at baseline (P interaction = 0.004). When adherence to the MedDiet was low, TT had higher fasting glucose concentrations (132.3 ± 3.5 mg/dL) than CC+CT (127.3 ± 3.2 mg/dL) individuals (P = 0.001). Nevertheless, when adherence was high, this increase was not observed (P = 0.605). This modulation was also detected for total cholesterol, LDL cholesterol, and triglycerides (P interaction < 0.05 for all). Likewise, in the randomized trial, TT subjects had a higher stroke incidence in the control group (adjusted HR 2.91 [95% CI 1.36-6.19]; P = 0.006 compared with CC), whereas dietary intervention with MedDiet reduced stroke incidence in TT homozygotes (adjusted HR 0.96 [95% CI 0.49-1.87]; P = 0.892 for TT compared with CC).

CONCLUSIONS

Our novel results suggest that MedDiet may not only reduce increased fasting glucose and lipids in TT individuals, but also stroke incidence.

Dietary intake and major food sources of polyphenols in a Spanish population at high cardiovascular risk: the PREDIMED study

BACKGROUND AND AIMS

Epidemiological data have shown an inverse association between the consumption of polyphenol-rich foods and the risk of cardiovascular disease or overall mortality. A comprehensive estimation of individual polyphenol intake in nutritional cohorts is needed to gain a better understanding of this association. The aim of this study was to estimate the quantitative intake of polyphenols and the major dietary sources in the PREDIMED (PREvención con DIeta MEDiterránea) cohort using individual food consumption records.

METHODS AND RESULTS

The PREDIMED study is a large, parallel-group, multicentre, randomised, controlled 5-year feeding trial aimed at assessing the effects of the Mediterranean diet on the primary prevention of cardiovascular disease. A total of 7200 participants, aged 55-80 years, completed a validated 1-year food frequency questionnaire (FFQ) at baseline. Polyphenol consumption was calculated by matching food consumption data from the FFQ with the recently developed Phenol-Explorer database on polyphenol content in foods. The mean total polyphenol intake was 820 ± 323 mg day⁻¹ (443 ± 218 mg day⁻¹ of flavonoids and 304 ± 156 mg day⁻¹ of phenolic acids). Hydroxycinnamic acids were the phenolic group with the highest consumption and 5-caffeoylquinic acid was the most abundantly ingested individual polyphenol. The consumption of olives and olive oil was a differentiating factor in the phenolic profile of this Spanish population compared with other countries.

CONCLUSION

In Mediterranean countries, such as Spain, the main dietary source of polyphenols is coffee and fruits, but the most important differentiating factor with respect to other countries is the consumption of polyphenols from olives and olive oil.

Design of the nutritional therapy for overweight and obese Spanish adolescents conducted by registered dieticians: the EVASYON study

BACKGROUND

Dietary treatment for obese adolescents should aim to ensure adequate growth and development, by reducing excessive fat mass accumulation, avoiding loss of lean body mass, improving well-being and self-esteem and preventing cyclical weight regain. The aim of this article is to describe the dietary intervention design and the methods used to evaluate nutritional knowledge and behavior in the EVASYON study (Development, implementation and evaluation of the efficacy of a therapeutic programme for overweight/obese adolescents).

METHODS/DESIGN

EVASYON is a multi-centre study conducted in 5 Spanish hospital settings (Granada, Madrid, Pamplona, Santander and Zaragoza), where 204 overweight/obese Spanish adolescents were treated in groups of 9 to 11 subjects over 20 visits. The study was implemented in two stages: an intensive, calorie-restricted period for the first 9 weeks, and an extensive body-weight follow-up period for the last 11 months. A moderate energy intake restriction was applied in the intensive period according to the degree of obesity, on the basis of a balanced diet supplying 50-55% of daily energy as carbohydrates; 30-35% as fats and 10-15% as proteins. In the intensive period, adolescents were prescribed both a fixed full-day meal plan for the first three weeks and a full day meal plan with different food-choices for 6 weeks. Later, adolescents received a flexible meal plan based on food exchanges for the follow-up period until the end of the trial. Data on food intake, dietary and meal-related habits and behavior were collected by means of dietary questionnaires. To analyse nutritional knowledge, adolescents were examined regarding nutrient concepts and food adoitems for a healthy diet with the appropriate tools. Participants were given nutritional information with complementary teaching material, which was available on the EVASYON website (www.estudioevasyon.com).

DISCUSSION

The dietary intervention of the EVASYON programme with a moderate calorie restriction for a limited period of time could be a good strategy in treating overweight and obese adolescents and that will be tested further. Moreover, combining fixed plan with free-choice menus may help adolescents and their families to make right decisions for every day meals.

Total polyphenol excretion and blood pressure in subjects at high cardiovascular risk

BACKGROUND AND AIMS

Dietary factors are critical for the prevention and treatment of hypertension, but data on the effects of specific nutrients on blood pressure (BP) are scarce. The aim of this study was to assess the relationship between total polyphenol excretion (TPE) in urine, as an objective measurement of total polyphenol intake and BP in an elderly population at high cardiovascular risk.

METHODS AND RESULTS

Cross-sectional substudy of 589 high-risk participants entering in the PREDIMED trial. BP was measured and TPE was determined in urine by Folin-Ciocalteu assay. A significant positive association was observed between TPE in urine and daily intake of fruit and vegetables (F&V), coffee or wine after adjusting for potential confounders. The intake of 100 g of F&V (Beta=0.150;P<0.001) had a greater contribution to TPE than 100 mL of coffee (Beta=0.141;P=0.001), and the latter two foods contributed more than the consumption of 100 mL of wine (Beta=0.120;P=0.019). An inverse association was observed between urinary TPE and the prevalence of hypertension. Participants in the highest quartile of urinary TPE had a reduced prevalence of hypertension compared to those in the lowest quartile (Odds Ratio=0.64; 95% confidence interval 0.45 to 0.92; P=0.015). Systolic and diastolic BP were inversely associated with urinary TPE after adjustment for potential confounders (P=0.024 and P=0.003, respectively).

CONCLUSIONS

Polyphenol intake, assessed via TPE in urine, was negatively associated with BP levels and prevalence of hypertension in an elderly Mediterranean population at high cardiovascular risk. Participants with the highest intake of polyphenol-rich foods showed the lowest BP measurements.

Breastfeeding in infancy is not associated with inflammatory status in healthy adolescents

It has been suggested that breast-feeding (BF) may be associated with a decreased risk of cardiovascular disease in adulthood. A low-grade inflammation is associated with an increased risk of cardiovascular disease, even in apparently healthy children. The objective of this study was to assess the potential modulating effect of BF on the inflammatory status of healthy adolescents. Information on BF (duration) was obtained from parental records in 484 of 1040 healthy European urban adolescents (56.4% females) that had a blood sample obtained as part of the Healthy Lifestyle in Europe by Nutrition and Adolescence study. Blood serum inflammatory markers were measured, including high sensitivity C-reactive protein, complement factors 3 and 4, ceruloplasmin, adhesion molecules (L-selectin and soluble endothelial selectin, soluble vascular cell adhesion molecule 1, and intercellular adhesion molecule 1), cytokines, TGFβ1, and white blood cells. After univariate analysis, a propensity score, including the potential confounding factors, was computed and used to assess the association between BF and selected inflammatory markers. BF was not significantly associated with any of the selected inflammatory markers after adjustment for gender and propensity score. In our study, BF was not associated with low-grade inflammatory status in healthy adolescents, suggesting that the potential cardiovascular benefits of BF are related to other mechanisms than modulation of inflammation or might become relevant at a later age. Groups at high risk for cardiovascular disease should be a target for further research concerning the effects of BF.

Passive smoking alters circulating naïve/memory lymphocyte T-cell subpopulations in children

While it has been indicated that exposure to second-hand smoke (SHS) can cause a local in vivo response, limited evidence exists on its possible systemic effects from population-based levels of exposure. We investigated into a possible systemic response in the immune parameters and lymphocyte subsets, i.e. B cell (CD19+), T cell (CD4+CD45RO+, CD4+CD45RA+, CD3+CD45RO+, CD3+CD45RA+) and natural killer (CD3+CD16CD56+) lymphocyte subsets relative to exposure to SHS. Blood was drawn from healthy, verified non-smoker, adolescent subjects (n = 68, mean age 14.2) and analysed for cotinine, antioxidants and lymphocyte immunophenotyping. SHS exposure was assessed using serum cotinine. Biomarker quantified exposure to SHS was correlated with a linear dose-response reduction in the percentages of memory CD4+CD45RO+ (p = 0.005) and CD3+CD45RO+ T-cell subsets (p = 0.005 and p = 0.003, respectively) and a linear increase in the percentage of naïve CD4+CD45RA+ and CD3+CD45RA+ T-cell subsets (p = 0.006 and p = 0.003, respectively). Additionally, higher exposure to SHS was associated with a higher CD4+CD45RA+ count (532 vs. 409 cells/ml, p = 0.017). Moreover, after controlling for age, gender, body mass index and plasma antioxidants, SHS exposure was found to be associated with the percentage of circulating naïve and memory CD4+ and CD3+ T-cell subpopulations, as revealed through a linear regression analysis. These findings indicate a systemic immunological response in healthy adolescents exposed to population-based levels of SHS exposure and imply an additional biological pathway for the interaction between exposure to SHS and its adverse effects on human health.

Gene-environment interactions of CETP gene variation in a high cardiovascular risk Mediterranean population

Genome-wide association studies show that cholesteryl ester transfer protein (CETP) single nucleotide polymorphisms (SNPs) are more strongly associated with HDL cholesterol (HDL-C) concentrations than any other loci across the genome. However, gene-environment interactions for clinical applications are still largely unknown. We studied gene-environment interactions between CETP SNPs and dietary fat intake, adherence to the Mediterranean diet, alcohol consumption, smoking, obesity, and diabetes on HDL-C in 4,210 high cardiovascular risk subjects from a Mediterranean population. We focused on the -4,502C>T and the TaqIB SNPs in partial linkage disequilibrium (D'= 0.88; P < 0.001). They were independently associated with higher HDL-C (P < 0.001); this clinically relevant association was greater when their diplotype was considered (14% higher in TT/B2B2 vs. CC/B1B1). No gene-gene interaction was observed. We also analyzed the association of these SNPs with blood pressure, and no clinically relevant associations were detected. No statistically significant interactions of these SNPs with obesity, diabetes, and smoking in determining HDL-C concentrations were found. Likewise, alcohol, dietary fat, and adherence to the Mediterranean diet did not statistically interact with the CETP variants (independently or as diplotype) in determining HDL-C. In conclusion, the strong association of the CETP SNPs and HDL-C was not statistically modified by diet or by the other environmental factors.

Neuroimmunomodulation by nutrition in stress situations

Stress has long been suspected to play a role in the etiology of many diseases and may be detrimental to health. Nowadays, the communication between the neuroendocrine and the immune systems is well established and there is enough evidence that the magnitude of stress-associated immune dysregulation is large enough to have health implications. In stress conditions, modulation of the immune system by the central nervous system (CNS) is mediated by a complex network of signals, showing a relationship between stress and resistance to infection. On the other hand, an adequate balanced diet plays a crucial role in the management of stress, and nutrition seems to be a critical determinant in the interactions among CNS and the immune system under stress conditions. Thus, interactions among nutrition, CNS and the immune system could be a key to understand implications in physiological stress situations. The present article will briefly review nutrition approaches on stress-related immune response and CNS communication.

Associations of low-grade inflammation with physical activity, fitness and fatness in prepubertal children; the European Youth Heart Study

OBJECTIVE

To examine the associations of low-grade inflammation with objectively measured physical activity, cardiovascular fitness (CVF) and fatness in prepubertal children.

DESIGN

Cross-sectional study.

SUBJECTS

One hundred and forty-two children (74 boys and 68 girls) aged 9-10 years (pubertal stage I and II) from the Swedish part of the European Youth Heart Study.

MEASUREMENTS

Total physical activity and its intensity levels (moderate, vigorous, moderate + vigorous) were measured by accelerometry. CVF was measured with a maximal ergometer bike test. Body fat was derived from the sum of five skinfold thicknesses. The measured low-grade inflammatory markers include C-reactive protein, fibrinogen, complement factors C3 and C4.

RESULTS

C-reactive protein and C3 were negatively associated with CVF (beta=-0.254 and -0.267, respectively, P<0.05) and positively associated with body fat (beta=0.439 and 0.446, respectively, P<0.001), after controlling for sex, age and pubertal development. C-reactive protein and C3 were not significantly associated with CVF once body fat was in the model. Low-grade inflammation was not associated with physical activity, but physical activity was associated with CVF.

CONCLUSIONS

The results showed that low-grade inflammatory markers were negatively associated with CVF and positively associated with body fat in prepubertal children. For most of the variables, the influence of fatness was slightly higher than the influence of CVF. The findings suggest that the potential beneficial effects of physical activity on low-grade inflammation may be explained by its association with CVF. Understanding the interplay between physical activity, CVF and fatness may be of importance to reducing cardiovascular disease risk in young people.

Cardiorespiratory fitness and sedentary activities are associated with adiposity in adolescents

OBJECTIVE

To determine whether physical activity, sedentary activities, and/or cardiorespiratory fitness are related to waist circumference in adolescents, as previously reported in adults.

RESEARCH METHODS AND PROCEDURES

The study subjects were a representative sample of Spanish adolescents (N = 2859; 1357 boys, 1502 girls; age, 13 to 18.5 years), all of whom were involved in the AVENA (Food and Assessment of the Nutritional Status of Adolescents) study. BMI, waist circumference, pubertal maturation status, and cardiorespiratory fitness were measured in all. Leisure-time physical activity, sedentary activities, active commuting to school, and socioeconomic status were assessed by self-reported questionnaires.

RESULTS

No relationship was found between leisure-time physical activity and BMI or waist circumference. In contrast, and in both boys and girls and after adjustment for confounding variables, cardiorespiratory fitness was found to be inversely associated with waist circumference and BMI, independent of sedentary activities or physical activity (p < or = 0.001). The maximum oxygen consumption explained 13% of the variance in waist circumference in boys and 16% in girls. Sedentary activities were independently and directly related to waist circumference in both boys and girls (p < or = 0.05) and to BMI in boys (p < or = 0.05). Sedentary activities explained 10% of the variance in waist circumference in boys and 18% in girls. The BMI-adjusted waist circumference was inversely correlated with cardiorespiratory fitness in overweight-obese boys (p < or = 0.05) and showed a trend toward significance in girls (p < or = 0.1).

DISCUSSION

Both moderate to high levels of cardiorespiratory fitness and sedentary activities, but not physical activity, are associated with lower abdominal adiposity, as measured by waist circumference.